Prevent voltage spike from reaching uno

[arduinoooo000b]

Hi Folks, my Arduino uno is getting voltage spike from the other components (water pump, solenoid etc). and that makes it go hay wire. how can I stop the spike from getting to uno? thanks

[jremington]

The best approach is to stop the voltage spike at the source, using an inductive kick diode across pump brushes or solenoid contacts, and a power supply that can handle the pump startup current (typically 5x to 10x higher than the free running current).

Also, power the Arduino and pump or solenoid separately and connect the grounds. The Arduino 5V output cannot be used to power pumps, solenoids or servos.

Inductive kick diode shown below:

[gilshultz]

@arduinoooo000b

my Arduino uno is getting voltage spike from the other components

Many will say solving EMI is black magic, I am not a magician but I have solved a few problems over the years. This might help. I posted it a while back.

Possible EMI (Electromagnetic Interference) Issue

This sounds like it could be related to EMI, either conducted or radiated. While I can't confirm this is the problem without more information, I also can't rule it out. Most MOS logic circuits are fast and sensitive to edge transitions. Minimizing lead lengths (which act as antennas) to less than 10 inches (25 cm) is crucial, as longer leads can pick up frequencies up to about 750 MHz, not accounting for reflections and other effects.

Tips to Reduce EMI:

1. Keep Connections Short: Both transmitters and receivers are affected by antenna length—longer antennas have greater gain and can pick up more interference. Use the KISS principle: Keep It Short & Simple.
2. Avoid Parallel Lines: Ensure power and logic lines are not running parallel to each other to minimize crosstalk and interference.
3. Use a Zero-Crossing Solid-State Relay: This can be a simple and effective solution to reduce EMI, especially when dealing with AC loads.

Historical Context: This issue has been known since the early 1960s with TCTL (Transistor-Coupled Transistor Logic), later known as TTL (Transistor-Transistor Logic). It prompted the development of line drivers and other technologies to manage EMI.

For further reading on related topics, check out these resources:

• Triac Principles and Circuits, Part 1: Learn about triacs, which are often used in switching applications and can be susceptible to EMI.
  Read Part 1
• Triac Principles and Circuits, Part 2: This article continues exploring triac applications and EMI considerations.
  Read Part 2
• Arduino Forum Discussion on Flashing LEDs: An example of EMI considerations in a practical Arduino project.

1. Shielding

• Shielded cables: Use cables with shielding (like braided metal or foil wraps) to reduce the amount of EMI they emit or pick up.
• Enclosures: Place sensitive electronics in metal or conductive enclosures (Faraday cages) to block external electromagnetic fields.

2. Grounding

• Proper grounding: Ensure that all electronic components and their enclosures are properly grounded to prevent stray electromagnetic signals from affecting them. Grounding can direct EMI away from sensitive components.

3. Ferrite Beads

• Ferrite beads: Install ferrite beads on cables that run to and from sensitive electronics. These components help suppress high-frequency EMI by dissipating it as heat.

4. Twisted Pair Cables

• Twisted pair wiring: If you're running wires, use twisted pair cables for signal lines. The twisting helps cancel out EMI that would otherwise be picked up by the wires.

5. Capacitors and Filters

• EMI filters: Install EMI filters (low-pass, high-pass, or band-stop) on power supply lines or signal lines to prevent high-frequency noise from reaching sensitive electronics.
• Capacitors: Capacitors between power lines and ground can help smooth out high-frequency noise.

6. Distance from EMI Sources

• Separation: Keep sensitive electronics as far away as possible from sources of EMI, such as motors, ignitions, and power cables.

7. Proper Cable Routing

• Avoid running signal cables near power lines, ignition systems, or any high-current cables to reduce the possibility of picking up interference.

8. Use EMI-Resistant Components

• Whenever possible, use components that are specifically designed to be resistant to EMI, such as EMI-hardened sensors, controllers, and processors.

9. Suppress Noise at the Source

• Suppress ignition noise: If close to an engine use resistor-type spark plugs or ignition leads with built-in suppression to reduce EMI from the engine and ignition system.
• DC-DC converters: For bikes with electric systems, install noise-suppressed DC-DC converters to minimize EMI from power supplies.

By implementing a combination of these techniques, you can significantly reduce the impact of EMI on your projects electronics. If you need help with a specific part or scenario, feel free to provide more details!